FIGURE 1.

Depleting GMFγ reduces B cell spreading on immobilized anti-Ig. (A,B) Ramos B cells (A) or Raji D1.3 B cells (B) were transfected with control non-targeting siRNA or GMFγ siRNA. Immunoblots (left panels) show GMFγ levels in cell extracts, with actin as a loading control. The transfected B cells were added to anti-IgM-coated-coverslips and allowed to spread for the indicated times before being stained with rhodamine-phalloidin. Representative confocal microscopy images are shown (right panels). Scale bars: 5 μm. (C,D) For each B cell, the cell area was quantified using the actin staining to define the cell edge. The left panels show data from representative experiments. Each dot represents one cell. The median (blue line) and interquartile ranges (black box) for > 30 cells are shown for each time point. p-values were determined using the Mann-Whitney U-test. The right panels show the mean ± SEM of the median cell areas from three independent experiments. Where no error bars are shown, they were smaller than the symbols. p-values were determined using paired two-tailed t-tests. ****p < 0.0001; **p < 0.01; *p ≤ 0.05; ns, not significant (p > 0.05).